
Philip P. answered 05/12/14
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2 1
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(x+5) (x-5)
Like any fraction, to add tow rational expressions you need to put them over a common denominator, in this case (x+5)(x-5)
2 *(x-5) 1*(x+5) 2x-10-x-5 x-15
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(x+5)(x-5) (x-5)(x+5) (x-5)(x+5) (x2-25)
------ ------ - ------------- = -------------- = ---------------
(x+5)(x-5) (x-5)(x+5) (x-5)(x+5) (x2-25)